Normal and pathological bowel sound patterns.

The purpose of this study was to determine the usefulness of auscultation of bowel sounds in evaluating patients with total and subtotal small intestinal obstruction and immediately after operation. The study was based on ten healthy volunteers, seven patients with documented mechanical obstruction, one patient with chronic subtotal mechanical obstruction and twelve patients undergoing an emergency laparotomy. Bowel sounds varied markedly in all individuals studied. The most striking finding in mechanical obstruction was the regular occurrence of clustered bowel sounds. These were defined as 3-10 regular sounds, occurring one every five seconds, preceded and followed by at least one minute of silence. The associated periods of quiescent motor activity may account for the unexpectedly reduced frequency and motility index after a meal in obstructed patients compared with normal subjects. The different bowel sound patterns occurred in the patient with subtotal mechanical obstruction before and after a meal respectively i.e. infrequent and low-amplitude bowel sounds and clustered bowel sounds. The technique is probably not more sensitive than radiological procedures, and the abnormalities that are detected by an auscultation of bowel sounds are not specific.